Access can handle 255 connections, but on the web this is increased further as IIS pools the connection.
When a page loads it take only 0.01 of a secound to process as soon as this is done the database connection is dropped anyway, so it isn't really that much of an issue.
The problem with Access is more to do with it being a flate file, so the larger is grows the larger the file that needs to be loaded into memory each time, thuse slowing down the forum, so you need to keep the database size down.